The answer is cooing and babbling. To simplify, kara has just begun to produce vowel sounds known as cooing while farina is delighting her parents by emitting all the sounds of human speech, which is called babbling. In addition, babies are doing cooing by making silly noises with their recently establish vocal cords and that babbling was experimenting with new sounds that they can make once they get used to their small tongues and mouths which is typically making consonant and vowel noises that are gaga, mama, baba and etc.